class Person:
  name = 'Willianm'
  age = 45
  def greet(self):
    print('Hi. my name is ' + self.name)

p1 = Person()
p1.age = 40
print('001', p1.age)
p1.greet()

p2 = Person()
print('004', p2.age) # 45
print('005', Person.age) # 45
p2.age = 18
Person.age = 17
print( '006', p2.age ) # 18
print( '007', Person.age ) # 17

# del p1.age
# del p1
# print(p1.age)
